Дисертації з теми "Non-Destructif Testing"
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Rodat, Damien. "Simulation opérationnelle en contrôle non destructif." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS535.
Several fields have already adopted the concept of operational simulation to limit risks and costs. For instance, part of the training phase of airline transport pilots or surgerons can now rely on simulations instead of real-life situations.Non-Destructive Testing (NDT) assesses the integrity of structural and mechanical components without damaging them. Operational simulation has drawn attention of the NDT community only recently through an Airbus patent. In this field, the operational simulation can be used to simulate the presence of a defect in a component without actually inserting the defect. For expensive parts such as aeronautical structures, this approach can reduce the costs of training operators, evaluating NDT method performances or testing new procedures in real-conditions.This thesis work aims to apply the concept of operational simulation to NDT. Three main scientific and technological challenges are to be tackled: the simulation realism, the computation speed and the instrumentation. We chose to focus this study on the ultrasound NDT technique applied to composite materials. Classical simulation approaches based on physical equations are not fast enough for a real-time synthesis of ultrasound signals. Moreover, the realism is often limited by the fidelity of the inspection set-up description. For instance, the material properties are not always well-known and bring to a drop of realism. Thus, we investigate an alternative way: the models are built directly from experimental data. This strategy is applied to model the effect of several phenomena such as impact damages, flat bottom holes or material micro-structure. Hardware and software solutions are also studied to propose a first prototype. We have shown that the replacement of real signals by on-the-fly simulated ones is achievable: the simulation is realistic enough to be considered as reality by operators. thus, this thesis work brings the concept to a first prototype dedicated to ultrasound NDT
Duan, Yuxia. "Probability of detection analysis for infrared nondestructive testing and evaluation with applications including a comparison with ultrasonic testing." Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25251.
The reliability of a Non-Destructive Testing and Evaluation (NDT& E) technique is one of the most important aspects of the overall industrial inspection procedure. The Probability of Detection (PoD) curve is the accepted quantitative measure of the NDT& E reliability, which is usually expressed as a function of flaw size. Every reliability experiment of the NDT& E system must be well designed to obtain a valid source data set, including the infrared thermography (IRT) technique. The range of defect aspect ratio (Dimension / depth) values is designed according to our experimental experiences to make sure it is from non-detectable to minimum detectable aspect ratio and larger. A preliminary test will be implemented to choose the best inspection parameters, such as heating energy, the acquisition time and frequency. In the data and image processing procedure, several important parameters which influence the results obtained are also described. For active IRT, there are different heating sources (optical or ultrasound), heating forms (pulsed or lock-in) and also data processing methods. Distinct heating and data processing manipulations produce different inspection results. In this research, both optical Pulsed Thermography (PT) and Lock-in Thermography (LT) techniques will be involved in the PoD analysis. For PT, PoD curves of different data processing methods are compared, including Fourier Transform (FT), 1st Derivative (1st D) after Thermal Signal Reconstruction (TSR), Wavelet Transform (WT), Differential Absolute Contrast (DAC), and Principal Component Thermography (PCT). Systematic studies on PoD analysis for IRT technique are carried out. Additionally, constructed PoD curves of IRT technique are compared with those obtained by other traditional NDT& E approaches.
Carcreff, Ewen. "Déconvolution adaptative pour le contrôle non destructif par ultrasons." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1009/document.
This thesis deals with the ultrasonic non destructive testing of industrial parts. During real experiments, the signals received by the acoustic transducer are analyzed to detect the discontinuities of the part under test. This analysis can be a difficult task due to digital acquisition, propagation effects and echo overlapping if discontinuities are close. Sparse deconvolution is an inverse method that aims to estimate the precise positions of the discontinuities. The underlying hypothesis of this method is a sparse distribution of the solution, which means there are a few number of discontinuities. In the literature, deconvolution is addressed by a linear time-invariant model as a function of propagation distance, which in reality does not hold.The purpose of this thesis is therefore to develop a model and associated methods in order to cancel the effects of acquisition, propagation and echo overlapping. The first part is focused on the direct model development. In particular, we build a linear time-variant model that takes into account dispersive attenuation. This model is validated with experimental data acquired from attenuative materials. The second part of this work concerns the development of efficient sparse deconvolution algorithms, addressing the minimization of a least squares criterion penalized by a L0 pseudo-norm. Specific algorithms are developed for up-sampled deconvolution, and more robust exploration strategies are built for data containing oscillating waveforms. By using synthetic and experimental data, we show that the developed methods lead to better results compared to standard approaches for a competitive computation time. The proposed methods are then applied to real non destructive testing problems where they confirm their efficiency
Trifonov, Andrey. "Contrôle non destructif par des méthodes d'acoustique non linéaire pour des applications aéronautiques." Thesis, Ecole centrale de Lille, 2017. http://www.theses.fr/2017ECLI0006/document.
This PhD thesis work contributes to the development of nonlinear elastic methods for non-destructive testing and imaging of contact-type defects in solids.In this work, two modifications of recent nonlinear nondestructive testing methods are suggested: the coda wave interferometry combined with the nonlinear time reversal principle and air-coupled nonlinear ultrasonic imaging. The principal advantage of former technique is in its extremely high sensitivity owing to the fact that weak changes in sample's parameters are accumulated and finally greatly amplified during the formation of the coda wave. The other technique has a complimentary strength and offers a possibility of a remote detection. The developed techniques are tested on samples with artificially fabricated defects at known locations. The performance of each method is accessed and the potential for obtaining robust nonlinear images is demonstrated.The second part of the work is concerned with a theoretical description of contact acoustical nonlinearity and its use for creating of a numerical toolbox capable of simulating wave propagation in complex structures containing internal contacts. A physical model describing the tangential shift of two contacting bodies in the presence of friction has been proposed. Its result is an analytical computer-assisted solution for hysteretic relationships between normal and tangential contact displacements and loads. The contact model and derived load-displacement relationships are used as boundary conditions posed at the internal boundaries (contact surfaces) in a finite element wave propagation model programmed via commercial software
Hesabi, Somayeh. "3D modeling of large elongated structures for non-destructive testing and inspection." Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27640.
According to a Central Intelligence Agency (CIA) report ¹ presented in a flagship NDT journal ², there were a total of 3.3 million km of pipelines present in 120 countries in the world in 2014. This means that pipelines play an important role in the energy infrastructure in order to safely transport liquid or natural gas. Although pipelines are the most efficient and reliable way to carry various liquids ranging from water to oil, they are vulnerable to external and internal damages. Fortunately, a periodic inspection of pipelines can increase their functionality and decrease the environmental disasters as well as economic losses caused by potential spills, explosions or other malfunctions. In this context of the exploitation of pipelines and other similar elongated structures and considering the benefits of 3D sensors which allow us to create an accurate digital replica of the surface of physical objects in addition to the advantages of Non-Destructive Testing (NDT) technology which provides the ability of under-surface monitoring, our research proposes a solution to build a 3D model of pipeline or other elongated structures to monitor their status. For this purpose, we first measure the geometry of the pipeline by handheld 3D scanners and construct the 3D model of the structure. Then, the information of subsurface defects that is estimated efficiently by approaches developed by other team members using infrared thermography is integrated to the reconstructed 3D model. The manuscript investigates different challenges related to the 3D modeling of large elongated structures with high accuracy and repeatability for quality control purposes as well as for long-term maintenance. 1. The World Factbook, updated 18 May 2015. 2. Materials Evaluation (M.E.), vol. 73, no. 7, July 2015
Dahia, Abla. "Contribution à la caractérisation non destructive de matériaux magnétiques sous contraintes par méthode électromagnétique." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112391.
The non-destructive evaluation (NDE) technique by eddy current (EC) is a conceivable solution to characterize the stress state in magnetic materials. The approach relies on the high sensitivity of eddy current (EC) signals to the magnetic permeability, itself highly dependent on stress. The EC technique is potentially attractive compared to other NDE methods such as X-ray diffraction, due to its simple practical implementation, easiness of automation and low cost. In order to allow eventually the inverse identification of stress states in magnetic materials, a predictive model for the evolution of an EC probe signal as a function of stress has been developed during this thesis. The modelling is done in two steps. First, the effect of stress on the magnetic permeability is described using a simplified version of a multiscale model for magneto-elastic behaviour. This approach allows describing the effect of multiaxial mechanical loadings on the magnetic behaviour of materials including induced anisotropy effects. Then, the EC probe signal is determined as a function of the anisotropic permeability of the stressed material using the finite element method (FEM). In order to validate the modelling approach, an experimental setup for magnetic characterisation and EC measurements was developed. The measurements show a good qualitative accordance with the modelling results, in absence of any calibration. A calibration procedure based on a measurement under stress is necessary to obtain a quantitative agreement. The proposed model can be used to design efficient EC probes and to define optimal operating conditions to evaluate stress in magnetic materials. The development of inversion procedures, however, remains a challenge
Raillon, Raphaële. "Mécanisme de formation des échos ultrasonores transitoires sur des cibles immergées de formes simples : application au contrôle non destructif." Châtenay-Malabry, Ecole centrale de Paris, 1993. http://www.theses.fr/1993ECAP0286.
Granados, Gerardo Emanuel. "Machine learning based simulation of realistic signals for an enhanced automatic diagnostic in non-destructive testing applications." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPAST143.
Model-based solutions for automatic diagnostics in the field of non-destructive testing are currently a topic of great interest in both academic and industrial communities. Their ultimate objective is to provide a qualitative or quantitative evaluation of the inspected material state (sound, flawed, flawed with anomaly dimensions or criticality) in an industrial context like a production line. Such tools, providing inputs for real-time process control, contribute to the general trend in Europe that aims at modernizing industry and services. The CEA LIST Institute is an internationally recognized research institution in non-destructive testing and evaluation (NDT&E). It develops the CIVA software, which offers multi-physics models and is considered a leading product for simulation for NDT&E applications. Accurate models able to reproduce experimental signals prove very helpful in an inversion process aiming at classifying or characterizing flaws. However, as they do not account for disturbances and parameter variability occurring during an experimental acquisition, simulated signals inherently look "perfect" and are, for instance, easily distinguishable from experimental data. This PhD subject aims to improve the match between simulation and experimental data by augmenting the simulation with another contribution generally referred to as "noise". The strategy proposed to obtain such noise contribution is to apply machine-learning techniques to a set of representative experimental data. Alternatively, a deep learning model can be trained to analyze "real" data and distinguish between contents (flaw signals) and style (the rest, which physical models do not simulate). Afterwards, the augmented simulation tool will be able to reproduce closely experimental data, account for specific discrepancies due to a particular environment and reproduce the variability observed experimentally. It will thus enhance the performance of model-based tools developed at CEA LIST for sensitivity analysis, management of uncertainty and diagnostic
Chouh, Hamza. "Simulations interactives de champ ultrasonore pour des configurations complexes de contrôle non destructif." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1220/document.
In order to fulfill increasing reliability and safety requirements, non destructive testing techniques are constantly evolving and so does their complexity. Consequently, simulation is an essential part of their design. We developed a tool for the simulation of the ultrasonic field radiated by any planar probes into non destructive testing configurations involving meshed geometries without prominent edges, isotropic and anisotropic, homogeneous and heterogeneous materials, and wave trajectories that can include reflections and transmissions. We approximate the ultrasonic wavefronts by using polynomial interpolators that are local to ultrasonic ray pencils. They are obtained using a surface research algorithm based on pencil tracing and successive subdivisions. Their interpolators enable the computation of the necessary quantities for the impulse response computation on each point of a sampling of the transducer surface that fulfills the Shannon criterion. By doing so, we can compute a global impulse response which, when convoluted with the excitation signal of the transducer, results in the ultrasonic field. The usage of task parallelism and of SIMD instructions on the most computationally expensive steps yields an important performance boost. Finally, we developed a tool for progressive visualization of field images. It benefits from an image reconstruction technique and schedules field computations in order to accelerate convergence towards the final image
Groz, Marie-Marthe. "Reconstruction 3D de sources de chaleur volumiques à partir des champs de température de surface mesurés par thermographie InfraRouge." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0135.
Non Destructive Testing (N.D.T.) of materials and structures is a very important industrial issue in the fields of transport, aeronautics and space and in the medical domain. Active infrared thermography is a N.D.T. method that consists in providing an external excitation to cause an elevation of temperature field in the material and then to evaluate the resulting temperature field at the surface. However, thermal exciters used (flash lamps, halogen, lasers) act only on the surface of the sample. Several energy conversion systems can on the other hand lead to the generation of volumetric sources: the phenomena of thermo-acoustic, thermo-induction, thermomechanic or thermochemistry can be cited. For example, ultrasonic waves can generate volumetric heat sources if the material is viscoelastic or if there is a defect. The reconstruction of these sources is the first step for the quantification of parameters responsible of the heating. Characterizing a heat source means reconstructing its geometry and the power it generates. For example, a defect in a structure and / or the viscoelasticity of a material can be detected and quantified by this technique if it acts directly on temperature field. However, identification of volumetric heat sources from surface temperature fields is a mathematical ill-posed problem. The diffusive nature of the temperature is the main cause. In this work, the 3D reconstruction of the volumetric heat sources from the resulting surface temperature field, measured by InfraRed, is studied. First, an analysis of the physical problem enables to specify the limits of the reconstruction. In particular, a criterion on achievable spatial resolution is defined and a reconstruction limitation for in-depth sources is highlighted. Then, a probabilistic approach for the reconstruction is proposed and compared to existing inverse methods. The computation time and noise sensitivity are studied for each of these methods. Numerical and experimental applications will thus be presented to illustrate the results
Lambert, Jason. "Parallélisation de simulations interactives de champs ultrasonores pour le contrôle non destructif." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112125/document.
The Non Destructive Testing field increasingly uses simulation.It is used at every step of the whole control process of an industrial part, from speeding up control development to helping experts understand results. During this thesis, a simulation tool dedicated to the fast computation of an ultrasonic field radiated by a phase array probe in an isotropic specimen has been developped. Its performance enables an interactive usage. To benefit from the commonly available parallel architectures, a regular model (aimed at removing divergent branching) derived from the generic CIVA model has been developped. First, a reference implementation was developped to validate this model against CIVA results, and to analyze its performance behaviour before optimization. The resulting code has been optimized for three kinds of parallel architectures commonly available in workstations: general purpose processors (GPP), manycore coprocessors (Intel MIC) and graphics processing units (nVidia GPU). On the GPP and the MIC, the algorithm was reorganized and implemented to benefit from both parallelism levels, multhreading and vector instructions. On the GPU, the multiple steps of field computing have been divided in multiple successive CUDA kernels.Moreover, libraries dedicated to each architecture were used to speedup Fast Fourier Transforms, Intel MKL on GPP and MIC and nVidia cuFFT on GPU. Performance and hardware adequation of the produced algorithms were thoroughly studied for each architecture. On multiple realistic control configurations, interactive performance was reached. Perspectives to adress more complex configurations were drawn. Finally, the integration and the industrialization of this code in the commercial NDT plateform CIVA is discussed
Peng, Tao. "Conception et réalisation de micro-capteurs à magnéto-impédance pour le contrôle non destructif." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112407/document.
The capability to detect micro-defects or buried flaws in the metallic parts is an important issue for the aerospace or nuclear industry. The technique of nondestructive testing (NDT) by eddy current is widely used for these applications. This thesis is part of collaboration project aimed at the realization and integration of magnetic field microsensors based on the magneto-impedance (MI) effect for the NDT detection systems. These multilayered structure microsensors (ferromagnetic/conductor/ferromagnetic) were realized in the clean room by thin film deposition method. A post-annealing step with magnetic field was then used to optimize the material properties and to induce magnetic anisotropy in the ferromagnetic layers. A method based on the double amplitude demodulation was proposed for the dynamic characterization of the sensors. The important parameters such as the geometry, the anisotropy and the driven frequency were studied in order to optimize the characteristics. The results showed that a bias field is necessary for the application. Therefore, we have investigated the possibility to realize, through thick micromoulding technique, a 3D microsolenoid and preliminary work on integrating a sensor in the microsolenoid by film transfer has been carried out. Finally, a theoretical study was investigated by taking into account the results obtained experimentally. For this purpose, the model of Landau-Lifshitz-Gilbert (LLG) has been implemented in an electromagnetic finite element calculation program in order to determine the impedance of the sensor as a function of the applied magnetic field
Stévenin, Mathilde. "Rayonnement des ondes ultrasonores guidées dans une structure mince et finie, métallique ou composite, en vue de son contrôle non-destructif." Thesis, Valenciennes, 2016. http://www.theses.fr/2016VALE0037/document.
Different models are developed to provide generic tools for simulating nondestructive methods relying on elastic guided waves applied to metallic or composite plates. Various inspection methods of these structures exist or are under study. Most of them make use of ultrasonic sources of finite size; all are sensitive to reflection phenomena resulting from the finite size of the monitored objects. The developed models deal with transducer diffraction effects and edge reflection. As the interpretation of signals measured in guided wave inspection often uses the concept of modes, the models themselves are explicitly modal. The case of isotropic plates (metal) and anisotropic (multilayer composites) are considered; a general approach under the stationary phase approximation allows us to consider all the cases of interest. For the first, the validity of a Fraunhofer-like approximation leads to a very efficient computation of the direct and reflected fields radiated by a source. For the second, special attention is paid to the treatment of caustics. The stationary phase approximation being difficult to generalize, a model (so-called “pencil model”) of more geometrical nature is proposed with a high degree of genericity. It chains terms of isotropic or anisotropic propagation and terms of interaction with a boundary. The equivalence of the stationary phase approximation and the pencil model is demonstrated in the case of the radiation and reflection in an isotropic plate, for which an experimental validation is proceeded
Destic, Fabien. "Imagerie térahertz utilisant des lasers à cascade quantique : application au contrôle non destructif de matériaux." Thesis, Toulouse, ISAE, 2014. http://www.theses.fr/2014ESAE0019/document.
Quantum Cascade Lasers (QCL) are "new" THz sources that have enjoyed remarkable progress in terms of power, operating temperature and beam quality. QCLs are used in continuous wave THz imaging setups applied to Non Destructive Testing of materials. A first qualitative application of NDT allows us to highlight defects in the fibers impregnation by resin or damages caused by an impact on composite materials. Transmission and reflection images at 3.8 THz are compared with a NDT ultrasonic technique. A second quantitative application relates to the water concentration in two hydrophobic polymeric materials: polystyrene and polypropylene. Establishing a relationship between the transmittance of the sample and mass water content enables us to draw up a quantified mapping of the latter. These maps are necessary for the understanding of the water diffusion process in polymeric materials
Hadadeh, Fawaz. "3D Probe for Magnetic Imaging and Non-destructive Testing." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS421/document.
The thesis is dedicated to the development of probes based on magnetoresistive sensors capable of detecting the three components of the field simultaneously for eddy current non-destructive testing and for magnetic imaging. A first part provides an overview of the state of the art of sensors, and imaging and control methods. In a second part, the realization of the three-axis probes is given. This included the micro-fabrication, the realization of the reading electronics, the design and realization of the mechanical part and emission. For this, an important simulation work was necessary. The application of these probes to model cases for magnetic imaging with submillimeter resolution is then described. The probe proposed in this thesis has also been used successfully to detect defects in aluminum and titanium samples with a good signal-to-noise ratio
Kuhn, Eric. "Contrôle non destructif d'un matériau excité par une onde acoustique ou thermique, observation par thermographie." Thesis, Paris 10, 2013. http://www.theses.fr/2013PA100177/document.
To detect a defect in a composite, several methods of non destructive testing have been developped. The aim of this work is to find a delamination in polymer matrix laminates thanks to two methods : thermosonics and thermography. The first method consists of an ultrasonic excitation and a detection by an IR camera. For the second technique, the plate is irradiated with a thermal wave and the detection is also performed by an IR camera. To compare the results, ultrasonic immersion tests were performed on the samples. This method provides a map of the delamination in the laminate. An algorithm for comparing the detection of delamination made by the ultrasonic C-scan and both methods revealed differences in the shape of the detected defect. Several image processing have been applied to the IR images recorded : temporal analysis and spatial / temporal analysis. The study of the instant evolution and the global evolution of the temperature are promissing for thermosonics. The most uncorrelated image obtained by principal component analysis gives is satisfactory for this method. For thermography, the non contact method, the phase study revealed the shape of delamination with the same precision as thermosonics.A comparison between the two methods was realised to highlight their advantages and their drawbacks
Frederique, Louis. "Identification et réduction de l’artefact métallique en tomographie à rayons X." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0014/document.
In the field of non-destructive testing of materials, computed tomography became a good way to check defects in industrial piece production. TomoAdour is a private compagny specialized in 3D digitization and x-ray computed tomography, it uses medical and industrial imaging techniques to analyze materials provided by his customers. However, tomographic analysis is difficult to achieve due to the presence of high density objects (such that metal) in most produced pieces, leading to the well-known metal artifacts in reconstructed data. In X-Ray tomography, metal artifact is characterized by a local and straight hyper-signal. This observed phenomenon is due to high attenuations of the rays in the high density materials. Many different approaches have been proposed for metal artifact reduction during the last decade. However, these methods have been developed for medical application and does not take into account physical limitations specific to industrial materials. Moreover, state-of-the-art approaches start their process from the original projection data, that is to say directly from the acquired data. In our context, only reconstructed image is available due to clinical scanner usage, and there is currently no metal artifact reduction method only based on these data. The goal of this work is first to propose a tool which permit identifying and measuring metal artifact in the reconstructed data in order to correct them. Then, our work take in interest in presenting methods developed for an industrial context[1; 2]
Smime, Fatima-Zahra. "Modélisation bidimensionnelle de la propagation ultrasonore dans le contexte d'un contrôle non destructif ultrasonore sur tubes sans soudure." Thesis, Valenciennes, 2018. http://www.theses.fr/2018VALE0043.
Résumé en anglais non disponible
Laroche, Nans. "Méthodes d'imagerie ultrasonore avancées et rapides pour le contrôle non destructif de matériaux atténuants et diffusants." Thesis, Ecole centrale de Nantes, 2021. http://www.theses.fr/2021ECDN0036.
The development of multi-element probes and continuous progress in electronics have favored the generalization of ultrasonic imaging methods for non destructive testing (NDT). In particular, the total focusing method is widely used due to its simplicity and real-time capability. Nevertheless, the resolution and contrast of the resulting images are limited due to the oscillating nature of the ultrasonic wave. This work addresses ultrasonic imaging from an inverse problem perspective. Retrieving the reflectivity map from ultrasonic measurements acquired with band-limited transducers is an ill-posedproblem. In this work, we develop inversion methods based on a regularization framework that enhances both the sparsity and the spatial smoothness of the reconstructed solution. Therefore, we assume that the reflectivity map is mainly homogeneous and possibly contains only few reflectors of small size. A first contribution describes the implementation and the inversion of a linear model that relates the raw, large-size, ultrasonic data to the reflectivity image, through a matrix containing the ultrasonic waveforms. A second contribution consists in projecting the previous model involving raw ultrasonic data in the space domain through a linear beamforming method. The size of the resulting model is therefore reduced, and its inversion can be interpreted as a deconvolution problem with a non stationary point spread function and colored noise. We hence propose an interpolation model in order to obtain a computationally efficient method. Finally, the last part of this work consists in applying the proposed methods to media with complex acoustic properties, such as frequency attenuation and dispersion, where the ultrasonic waveform is distorted during propagation. These algorithms are applied to synthetic data and practical NDT cases and show superior resolving capabilities compared to standard methods, at the cost of higher computational complexity
Christophe-Argenvillier, Alexandra. "Méthode des éléments finis avec joints en recouvrement non-conforme de maillages : application au contrôle non destructif par courants de Foucault." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112341/document.
This thesis aims at studying and developing a domain decomposition method with overlapping subdomains for the modeling in eddy current (EC) non-Destructive testing (NDT). The idea behind such an approach is the possibility to avoid the systematic remeshes of the whole studying domain when some of its components are modified (for example the displacement of the coil above the conductor). More precisely, this work aims at designing a domain decomposition method with overlapping based on the theory of the mortar finite element method. In addition to remove the constraint owing to an coupling interface which is invariant with the displacement, the technique described, in this work, realizes reciprocal transfers of information between subdomains. This study presents the theoretical and numerical results attached to the magnetodynamic simulation. Moreover, the interest of such a method is illustrated by applications in some 2D modeling cases of EC NDT
Miorelli, Roberto. "Modélisation du contrôle par méthodes électromagnétiques de défauts réalistes de type fissuration." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112302.
Non Destructive Testing (NDT) with Eddy Current (EC) techniques are is widely employed in several industrial sectors for cracks detection. Numerical simulation tools are largely used in order to design sensors, understand the signals collected during the measurements process and to provide a support in expertise. This work has been accomplished inside CEA LIST in collaboration with L2S-Supélec. It is also a part of the CIVAMONT 2012 project, with the active participation of MEANDER laboratory members from University of Western Macedonia (Greece) and Technological Educational Institute of Western Macedonia (Greece). The main goal of our work has consisted in to developing a semi-analytical modeling approach, devoted to Eddy Current Testing (ECT) of multiple narrow cracks in planar multilayered structures. From the numerical point of view, simulation of multiple narrow cracks problems is a difficult task for classical methods, like for example the Volume Integral Method (VIM) or the Finite Element Method (FEM). The main issues reside in geometrical characteristics of narrow crack themselves. Indeed, a narrow crack presents a small opening as well as complex profile and a complex shape, with possible electrical contacts inside it. All these features increase enormously, with classical methods, the difficulty to simulate in rapid and/or precise way problems involving narrow cracks. We have tackled the narrow crack issue by developing a Boundary Element Method (BEM) dedicated to ECT signal modeling, starting from an approach presented in literature. Then, we have extended its capability to more realistic and challenging cases, such as the ECT of multilayered structures affected by complex narrow cracks. The principle of this method is to introduce additional assumptions, leading to the description of the crack perturbation as the effect of a dipole distribution, oriented toward the crack opening. Numerically speaking, such a description makes it possible to largely reduce, compared to the VIM, the number of unknowns that one needs to properly solve the problem. A particular attention has been devoted to the analytical formulation, in order to achieve generality, accuracy and efficiency. A precise derivation of the spectral-domain Dyadic Green Function (DGF) associated to our problem has first been developed. In this work, analytical expressions of the spectral-domain DGF have been obtained via the Discrete Complex Image Method (DCIM). Then, an accurate approximation of the spectral-domain DGF has been achieved via the Generalized Pencil of Function (GPOF) method. Therefore, the closed-form of the spectral-domain DGF, expressed under the form of Sommerfeld Integrals (SIs), has been calculated analytically. Finally, the integral equation(s) associate to the electromagnetic problem is solved by applying the Method of Moments (MoM).Validations with respect to experiments and commercial simulation software have been performed to test the model. A large set of configurations have been chosen in order to address realistic configurations involving multiple narrow cracks embedded in different layers of a given multilayered structure. The model proposed has shown its promising performance in terms of computational time compared with the VIM and the FEM. Moreover, a very good agreement with respect to the experimental data has always been observed. In the last and very recent part of our work, a coupled approach between BEM and VIM has been studied and developed in order to address, in a efficient way, problems where narrow cracks appear in the vicinity of with volumetric flaws (for example the simulation of fastener sites inspections). Comparisons with experimental measures have shown that the coupled approach is capable to achieve, overall, better results than the VIM and saves a lot of computational time
Morard, Vincent. "Détection de structures fines par traitement d'images et apprentissage statistique : application au contrôle non destructif." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00932727.
Peycheva, Kira. "Nondestructive testing of metals and composite materials using ultrasound thermography : Comparison with pulse-echo ultrasonics." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29592/29592.pdf.
Wang, Li. "Fast and Accurate 3D X ray Image Reconstruction for Non Destructive Test Industrial Applications." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS362/document.
2D and 3D X-ray Computed Tomography (CT) is widely used in medical imaging as well as in Non Destructive Testing (NDT) for industrial applications. In both domains, there is a need to reduce the number of projections. In some cases we may also be limited in angles. The measured data are always with errors (measurement and modelling errors). We are consequently almost always in the situation of ill-posed inverse problems. The role of the probabilistic methods and the prior modelling become crucial. For prior modelling, in particular in NDT applications, the object under examination is composed with several homogeneous materials, with several continuous blocs separated by some discontinuities and contours. This type of object is called the piecewise-continuous object. The focus of this thesis on the reconstruction of the picewise continuous or constant, or more generally piecewise homogeneous objects. In summary two main methods are proposed in the context of the Bayesian inference. The first method consists in reconstructing the object while enforcing the sparsity of the discrete Haar transformation coefficients of the object. A hierarchical Bayesian model is proposed. In this method, the unknown variables and parameters are estimated and the hyper-parameters are initialized according to the definition of prior models. The second method reconstruct objects while the contours are estimated simultaneously. The piecewise continuous object is modeled by a non-homogeneous Markovian model, which depends on the gradient of the object, while the gradient also depends on the estimation of the object. In this methods, the semi-supervised system model is also achieved, with the parameters estimated automatically. Both methods are adapted to the 3D big data size reconstructions, in which the GPU processor is used to accelerate the computation. The methods are validated with both simulated and real data, and are compared with several conventional state-of-the-art methods
Zorni, Chiara. "Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112031/document.
The aim of this work is the eddy-current testing (ECT) of ferromagnetic materials within magnetic sensors, such as Giant Magneto-Resistances (GMR). Two complementary aspects have been studied. Experimental measurements have been carried out in order to quantify and minimize the noise coming from the materials structure and residual magnetization. On the other hand, a model has been developed in order to be able to simulate the electromagnetic interactions between a ferromagnetic specimen and the EC probe. The GMR sensors are characterized by high sensitivity at low frequency, large dynamic range and are relatively easy to implement. The studies carried out during this thesis allowed us to identify and analyse the “ghost signals” due to magnetic materials. In order to minimize the noise coming from the materials structure, a linear multi-frequencies combination of experimental signals has been employed successfully and the detection of buried flaws has been improved. The residual magnetization in ferromagnetic materials has been experimentally analyzed and an electronic system has been realized to fix the polarisation point of the sensor in the linear response zone of the GMR. Thus, disturbances caused by residual magnetization are successfully reduced. Beside, in order to develop simulation tools aiming at improving the understanding of experimental signals and optimizing the performances of ECT procedures, a model has been developed to simulate the ECT of planar, stratified and ferromagnetic materials affected with multiple flaws. CEA developed for many years semi-analytical models embedded into the simulation platform CIVA dedicated to non-destructive testing. Following a previous work carried out at the laboratory and already integrated in the simulation platform CIVA, developed at CEA-LIST, the new model extends CIVA functionalities to the ferromagnetic planar case. Simulation results are obtained through the application of the Volume Integral Method (VIM) which involves the dyadic Green’s functions. Two coupled integral equations have to be solved and the numerical resolution of the system is carried out using the classical Galerkin variant of the Method of Moments (MoM). Finally, the probe response is calculated by application of the Lorentz reciprocity theorem. A collaboration with the University of Cassino (Italy) and Laboratoire de Génie Electrique de Paris (France) allowed us to compare the three models on experimental and numerical results from literature. Results showed a good agreement between the three models and the model stability has been analyzed
Verma, Ravi. "Interaction of ultrasonic waves with frictional defects in the context of nondestructive testing of materials." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILN063.
This thesis concerns theoretical concepts, models, and experiments for elastic wave propagation and vibrations in solids containing internal contacts (cracks, delaminations, etc.) having frictional nature. The study is oriented to nondestructive testing and therefore focuses on the case where the material contains few cracks of known configuration, in contrast to microcracked solids in which a statistical ensemble of a large number of internal contacts is present.An essential part of the work is related to a development of a method of numerical acoustics capable of imitating elastic waves in an environment containing frictional cracks/contacts. These planar defects represent a sort of inner boundaries at which appropriate boundary conditions should set. These boundary conditions are set using an original model for frictional interaction based on Cattaneo-Mindlin (or Hertz-Mindlin) mechanics in which two spheres are mechanically excited with an oblique force. The known solutions are extended to the case of rough surfaces and arbitrary in time oblique excitation.Another component of the numerical acoustics model we present here is a standard finite element description for elastic waves in solid materials (solid mechanics unit in a commercial FEM package). Some technical efforts have been made to integrate a user-defined contact model as a boundary condition into the solid mechanics unit. As a result, a complete model has been obtained that incorporates wave-induced contact frictional interactions described starting from first principles of contact mechanics.An essential progress in comparison to previous works is related to application of the elaborated model to a case that corresponds to a known technique of nonlinear acoustic nondestructive testing. The chosen technique is based on excitation of a sample with a harmonics wave that, after completion of a transient regime, results in a purely harmonic response of an intact sample, whereas the response of a damaged sample will present anharmonicity. The generated harmonics form its own standing wave pattern that can have a clear maximum around the defect. In practice, surface signal measurements are done via laser vibrometry; our modeling therefore represents an attempt to imitate laser vibromenry NDT experiment in geometrically simplified conditions, but fully adhering to its ideology.The simplified conditions are taken in a way that reduces the computation time. The most important assumption is a 2D geometry that immediately disables a quantitative comparison to experiment. Other simplifications are discussed below in greater detail. Keeping, however, the general methodology close to experimental principles we generate a large number of synthetic nonlinear images of an isolated crack immersed into a fragment of a solid plate. We analyze in detail influence of geometric and physical parameters of the system in the cases of one- and two-frequency excitations.Finally, we focus on the case close to real experimental conditions in terms of the sample geometry and boundary conditions selected. A preliminary theory and experiment comparison is presented.Generally, the results of this thesis could be of interest for researchers involved in nonlinear acoustic NDT experiments as well as for those who look for applications of modern semi-analytical contact models based on Cattaneo-Mindlin principles
Vasseur, Julien. "Fiabilité prévisionnelle de la tenue en service de composants mécaniques en présence d’amas de porosités détectés et caractérisés par contrôle non destructif ultrasonore." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2020. http://www.theses.fr/2020MTLD0002.
This work aims at defining a methodology for the lifetime estimation of aluminum alloy structures (aluminum 7075-T6) according to the properties of porosity clusters contained in the sample. We chose to use advanced ultrasonic imaging techniques to detect and characterize these porosities and then to correlate the ultrasonic images obtained with fatigue measurements. In the framework of our study, the problem is simplified with a 2D study where the cluster of porosities is represented as a set of side-drilled holes (SDH) whose geometric characteristics are fully controllable, unlike those of real porosity. A special effort is made to estimate the effects of multiple scattering due to wave interactions between defects. A comparative study of the imaging model thus developed is carried out by comparing our simulations including multiple scattering with other simplified simulation results (carried out on CIVA software) but also with experimental measurements. Concerning fatigue study, a phenomenological approach is suggested to take into account multi-cracks initiation and local multi-mode behaviour generated by the cluster of defects. Therefore, crack propagation is solved by a G-Ө finite element method for prediction of the fatigue lifetime of different samples with different cases of cluster of defects. Numerical and experimental results were compared showing that the suggested methodology gives realistic lifetimes despite of complexity of the studied cases. Finally, the overall originality of this thesis consists in making a direct link between NDT results and fatigue calculation. Thus, a method for estimating the fatigue life of a specimen based on inversed ultrasonic images of defects is suggested and applied on some studied cases
Jacquet, Olivier. "Méthodes de faisceaux gaussiens pour la modélisation d'ondes de volume ultrasonores : application à la simulation du contrôle non-destructif." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS204.
This works is part of the CIVA software development. CIVA is dedicated to non-destructive testing (NDT) simulation, and especially to efficient ultrasonic bulk wave simulation. However, its modeling approach, based on the ray theory under high frequency assumption, may suffer – in some specific cases – from caustics and shadowing effects. Gaussian beams are known to be suitable candidates for removing those singularities, and the purpose of this research work is to develop and validate an efficient computing method using Gaussian beam superpositions. A preliminary review of literature revealed an underlying problematic related to the Gaussian beam initialization. Indeed, there is no standard method for initializing a relevant set of Gaussian beams: existing approaches differ, depending on the authors and on the examples they discuss. From the perspective of NDT modeling, it is still necessary to develop a numeric solution which is generic enough to indiscriminately handle a wide variety of materials, geometries and input data. One way of adressing Gaussian beam initialization is - for a given problem - to obtain a frame representation of the initial and/or boundary conditions. By choosing a Gaussian kernel, it is then possible to generate an unequivocal set of initial Gaussian beam parameters. Finally, the approximated solution is given by the corresponding propagated Gaussian beams. In this work, we derived this frame approach in both time and frequency domains. The main contribution of this thesis research lies in the quantitative validation of this method, through typical configurations of ultrasonic NDT
Guihard, Vincent. "Homogénéisation de grandeurs électromagnétiques dans les milieux cimentaires pour le calcul de teneur en eau." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30165/document.
Prediction of delayed behavior in concrete can be significantly improved by monitoring the amount and spatial distribution of water within a concrete structure over time. Water content of cement-based materials can also be required to interpret non-destructive tests such as ultrasonic and radar measurements. Electromagnetic properties of heterogeneous and porous materials, such as dielectric permittivity, are closely related to water content. Measurement of these properties is thus a common non-destructive technique used to assess the moisture content, but a calibration curve is required to link the measured permittivity to the saturation degree. This curve can be determined experimentally, or from empirical models. However, the first approach is tedious and time consuming, while the second one is not adapted to concrete. Hence, this contribution proposes an alternative route, relying on electromagnetic homogenization schemes, to connect the macroscopic permittivity of cement-based materials with the water content of the structure. Therefore, different open-ended coaxial probes were designed, modelled and tested in order to perform complex permittivity measurements of both solids and liquids. The homogenization approach is first validated on unsaturated sand. Then, the permittivity of concrete components (aggregates, hydrates, interstitial liquid, anhydrous cement) was assessed by means of coaxial probe measurements. Finally, a specific combination of analytical homogenization laws taking into account the microstructure's morphology of the material is built. Results show that there is a good correlation between the model and measurements acquired on different cement pastes, mortars and concretes, at different saturation degrees. The model is characterized by a quasi-instantaneous calculation time and can be adapted to different concretes depending on cement type, nature and quantity aggregates or porosity
Merabet, Lucas. "Etude d’algorithmes de reconstruction ultrasonore dans le domaine de Fourier pour l’imagerie rapide 2D et 3D en contrôle non- destructif." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLET060.
This research work deals with ultrasound imaging with transducer arrays for Non Destructive Testing (NDT), and aims at speeding up the formation of 2D and 3D images. The methods studied in this manuscript are inspired from reconstruction algorithms in the Fourier frequency-wavenumber (f-k) domain introduced in seismic imaging in the 70’s. The literature shows that f-k methods offer a numerical advantage over the more conventional time-domain focusing algorithms. On the other hand, the rise of transducer arrays has allowed for the exploration of new emission modes, such as plane wave emissions in ultra-fast medical imaging. In this thesis, we propose to combine fast f-k algorithms with plane wave emissions to form 2D and 3D images as fast as possible. These algorithms are adapted to deal with realistic NDT inspection configurations. Analyses of algorithmic complexities, computation times, and image qualities are carried out in 2D, and a comparison with the time-domain Plane Wave Imaging (PWI) shows a clear advantage for f-k methods. This is confirmed in 3D, where we show that Fourier domain algorithms improve image quality while reducing computation times by a factor up to 300 compared to PWI. Finally, the f-k methods are generalized to multi-modal imaging to characterize cracks. The theory, which accounts for mode conversions and reflections at the specimen interfaces, is first presented, and we then demonstrate that it is possible to improve the reconstruction quality thanks to spectral windowing in the image frequency-domain. This spectral filter cancels undesired artifacts caused by interface echoes, and improves the image contrast
Pomarede, Pascal. "Détection de l'endommagement dans un composite tissé PA66,6/Fibres de verre à l'aide de techniques ultrasonores en vue d'une prédiction de la durabilité de pièces automobiles." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0024/document.
The present study is focused on the experimental study of a polyamide 66/6 based composite reinforced by a 2/2 twill weave glass fabric. The aim is to propose Non Destructive Evaluation (NDE) methods based on ultrasound that can efficiently distinguish different damage state. In order to do so, an investigation of the damage mechanisms induced by different type of mechanical solicitations. Tension along and off the axis of the fibers was considered as well as the case of drop weight impact. Those solicitations were shown to induce different damage mechanisms. The latter were characterized by means of Scanning Electronic Microscopy (SEM) and X-Ray tomography mostly. The decreasing of the elastic modulus and the void volume fraction evolution were shown to be more significant for the samples loaded in tension off-axis. During the drop weight impact tests, the energies were considered in order to remain close to the Barely Visible Impact Damage (BVID) regime in order to experience the capability of the ultrasound based NDE methods. Two NDE methods investigated during this study deserve to be highlighted. Firstly, the stiffness tensor was estimated by means of phase velocities measurements in different propagation direction. Damage indicators based on results from this method were proposed. They were found to give results similar with the one from the evaluation of damage discussed earlier on. Secondly, a study of the damage detection using guided waves was performed. No mode conversion effect was observed from this investigation. Consequently, the signal energy was proposed as damage indicator and was found to be suitable to detect damage induced by tension but not by impact. The measure of time shift allowed obtaining a localization and evaluation of the damage induced by impact
Barras, Jordan. "Prédiction modale du rayonnement d’ondes élastiques guidées par une source quelconque dans une structure fine - application au contrôle non destructif." Electronic Thesis or Diss., université Paris-Saclay, 2020. http://www.theses.fr/2020UPASG020.
This thesis focuses on the modelling of the propagation of elastic guided waves (GW) in thin plate like structures for their non-destructive testing (NDT). These waves are generated by any ultrasonic transducer positioned on the surface of the piece - for example, a PZT ceramic or an EMAT. A semianalytical model, the so-called GW modal pencil model, has been developed. It is based on the geometrical acoustic approximation, which makes it particularly efficient from a numerical point-of-view and able to simulate GW propagation over long distances faster than with conventional numerical models. The displacement field is then predicted only at the points of interest. The pencil model can be used to generically deal with multiple reflections of GW on plate edges. It also takes into account plates made of either metallic (isotropic) or composite (anisotropic) materials. The plate can be curved and have continuously variable mechanical properties. The waveforms are obtained in the form of their modal decomposition, which greatly eases their interpretation. Finally, comparisons with a finite element model allow the pencil approach to be validated
Lei, Lei. "Cold food chain : infrared thermography applied to the evaluation of insulation anomalies in refrigerated vehicles for the transport of food & exploration of cold approach in infrared thermography for non-destructive testing." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/31430.
The increasing cost of energy has made energy saving a vital necessity in the current world. One of the examples involves, “Maintaining the cold chain”, which is the correct transport of perishable foodstuffs in refrigerated vehicles, especially for dairy products, meat and frozen foods. In this respect a suitable thermal insulation implemented in refrigerated vehicles is essential for saving energy while maintaining an appropriate conservation of the foodstuffs. ATP (Agreement on Transport of Perishable Foodstuffs) is one of the agreements concerning thermal insulation tests ensuing the suitability of the transport. The ATP standard test is a procedure to measure the insulating status of equipment with a global approach. Nonetheless, some local defects in the structure of equipment cannot be visualized in this procedure. The thermography technique could be particularly helpful for these issues. Two examples of this application are presented in this thesis, one focuses on mapping the heat flux on the external surface of an insulated rollcontainer by infrared thermography technique. The second one attempts to establish a panoramic view of the heat flux on the internal surface of an insulated vehicle. Encouraged by previous favorable results, an exploration of the cold approach in infrared thermography for Non-Destructive Testing & Evaluation is introduced and performed herein. One approach focuses on the detection of insulated flaws and thermal bridges in insulated truck box panels by lamp heating and air cooling, two opposite means of excitation. The other approach investigates the application of liquid nitrogen cooling to a steel specimen with flat-bottom holes of different depths and sizes. Different data processing methods and modeling and simulation are also carried out.
Nagaso, Masaru. "Etude de la propagation des ultrasons dans un milieu fluide hétérogène en vue de la surveillance en fonctionnement d'un réacteur nucléaire à caloporteur sodium." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0197/document.
The ASTRID project, a french sodium-cooled nuclear reactor of 4th generation, is currently under development by the french alternative energies and atomic energy center (CEA). In this project, development of monitoring techniques is identified as an important issue to improve the plant safety. The use of ultrasonic measurement techniques is regarded as a powerful inspection tool due to the opacity of liquid sodium. Inside a cooling circuit, heterogeneity of the medium occurs because of a complex flow state, and then the effects of this heterogeneity on acoustic wave propagation are not negligible. Thus, it is necessary to carry out verification experiments, and such kind of experiments using liquid sodium may be large-scale. This is a reason why numerical simulation methods are essential. The objective of the study in the thesis is to apply a 3D spectral-element method, that we will show to be suitable to our targets more accurately than more classical numerical simulation methods.We will first study the development potential of ultrasonic thermometry in a liquid fluctuating sodium environment similar to that present in a sodium-cooled fast reactor with 2D simulation. Gaussian random process will be applied to generate fluctuations of temperature. To investigate 3D heterogeneity and more realistic temperature fields in the medium, in a second part of the thesis we will carry out a numerical study for 3D models of the reactor core. To represent the heterogeneity of liquid sodium, a four-dimensional temperature field (three spatial and one temporal dimension) calculated by computational fluid dynamics based on a large-eddy simulation performed by CEA STMF will be applied
Ahmed, Shamim. "Développement d’une méthodologie robuste d’inversion dédiée au CND par courants de Foucault." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS043/document.
The research activity of the PhD thesis focuses on the study and development of innovative strategies for the solution of inverse problems arising in the field of Non-Destructive Testing and Evaluation (NDT-NDE), based on the use of statistical learning theory. Generally speaking, the objective of the optimization stage is the retrieval of the unknown parameters within the studied electromagnetic scenario. In the case of NDT-NDE, the optimization problem, in terms of parameters to estimate, is divided into three stages, namely detection, localization and characterization. This work mainly addresses localization and characterization of crack(s) and/or estimation of probe(s) parameters. Unknown parameters, constituting a subset of the parameters set describing the electromagnetic scenario, are robustly estimated using several approaches. Standard optimization approaches are based on the minimization, by means of iterative approaches like stochastic and/or deterministic algorithms, of a cost function describing the discrepancy between measurements and prediction. This thesis considers the estimation problem in a machine learning perspective, adopting well known Learning-By-Example (LBE) paradigm. In a so-called offline phase, a surrogate inverse model is first fitted on a set of known input/output couples, generated through numerical simulations. Then, in a so-called online phase, the model predicts unknown outputs (the parameters of interest) based on new inputs (measured NDT signals) in quasi-real time. When considering practical inspection situations, due to the large number of variables involved (known as curse of dimensionality), obtaining an accurate and robust model is not a trivial task. This thesis carries out a deep and systematic study of different strategies and solutions to achieve simultaneously good accuracy and computational time efficiency in the parameters estimation. Moreover, a particular emphasis is put on the different approaches adopted for mitigating the curse of dimensionality issue. The proposed LBE schema has been tested with success on a wide set of practical problems, using both synthetic noisy data and experimental measurements
Liu, Zicheng. "Electromagnetic modeling and imaging of damages of fiber-reinforced composite laminates." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS332.
My PhD work is about electromagnetic modeling and imaging of disorganized periodic structures. A certain pattern in an elementary subdivision (a “cell”) is repeated in the other cells of the structure into certain directions of space. This repetition is disorganized by a change of material properties and/or geometries of the constitutive parts, within one or more cells. At first level of modeling, these panels are a succession of planar plates one over the other. Each consists of a regular linear arrangement of long cylinders with same finite circular sections, all orientated into the same direction: we call them “fibers”, each cylinder resulting from the assumption of a bundle of small-size fibers. The constitutive material of the fibers differs from the embedding material (matrix) that they reinforce. Each plate is made of fibers with different axes for sturdiness. There are few or many plates, with repetition of a small stack of plates. For conductive panels (carbon-based), imaging is MHz; for lossless or weakly lossy panels (glass based), imaging is microwave (a few tens GHz, possibly more). There might be missing/displaced cylinders inside a plate, with consequent changes in possibly several cells, adjacent or not. Local damages might occur also, leading to changes in shape or electromagnetic properties of one or more cylinders in one or more cells in one or more plates. Randomness in distribution of the inclusions might account for uncertainties of positioning with respect to assumed geometries. Properly illuminating the structures and collecting the resulting fields (in the near-field hopefully, possibly in the far-field) should allow their imaging and concur to their diagnostics. So, a periodic structure under interrogation is disorganized. One wishes to successfully image the structure while taking care at best of prior information on periodicity and disorganization, on sensing systems, and obviously of needs and limitations of the testing. The PhD benefits from a grant from the Chinese Scholarship Council
Ciccarone, Charles. "Utilisation d'ondes de surface à l'aide de scanners acoustiques sans contact pour le contrôle non destructif de structures en béton." Thesis, Ecole centrale de Lille, 2020. http://www.theses.fr/2020ECLI0014.
This work proposes a method for the non-destructive testing of concrete for civil engineering structures.This method is based on the emission and reception - when the surface wave has passed through the material - ofacoustic sonic and ultrasonic waves. The waves used in this thesis are surface waves, as they have the property ofpenetrating the material to a depth equal to their wavelength. The auscultation of concrete is done using twoscanners: a first scanner applying this method with high frequency waves was used to characterize the concreteskin, while a second scanner using low frequency waves, developed within the framework of this work, made itpossible to characterize a concrete over the thickness of an entire wall. In order to determine the capabilities andlimitations of this method for the non-destructive testing of concrete, several pathologies or environmentalconditions of concrete were simulated in the laboratory on test specimens. These specimens were then examinednon-destructively with acoustic scanners and destructively with material tests. The pathologies or conditions inquestion were leaching, delamination, micro/macrocracking of the concrete, and its state of saturation. Comparisonof the results allowed us to conclude that this method and these scanners are able to detect and determine the depthof a leaching of concrete, as well as for a delamination within concrete, to follow the evolution of a saturation frontwithin a limestone but not yet within a concrete, and to detect and follow the stress and micro-cracking as well asthe evolution of macro-cracks, in particular thanks to automated measurements carried out in situ on the VeRCoRsstructure
Kouadio, Thierry. "Thermographie infrarouge de champs ultrasonores en vue de l’évaluation et du contrôle non destructifs de matériaux composites." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14824/document.
The composite materials are widely used in industry because of their high mechanical resistance and low density. The diversity of composite materials application fields gives rise to a large variety of solicitation and damage conditions. For this reason, the evaluation of their properties and their health monitoring are of great industrial interest. In this work, a new method of evaluation and non-destructive testing named sonothermography is explored. This method is based on the analysis of thermal fields induced by ultrasonic waves in absorbent materials such as composites. Two additional applications are studied: the evaluation of the thermal properties of the material and the non-destructive testing of structures by infrared thermography. In this framework, the direct problem of sonothermography is solved numerically using a model based on the finite element method. This model allows to simulate the thermal field induced by the propagation of ultrasonic waves in absorbent material whose properties are known. The simulations carried out show the applicability of the sonothermography for the detection of defects. An innovative approach for thermal characterization is also developed. This approach based on the weak formulation of the heat conduction equation allows a robust estimate of the thermal diffusivity of the material from the thermal field induced by ultrasonic waves. Experimental results are presented for thin plates
Thiam, Abdoulahad. "Contribution à l’étude et à l’optimisation du procédé de thermographie active appliquée à la détection de défauts surfaciques." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCK040/document.
The aim of this work is the detection of open and subjacent defects in metallic materials using laser-material interaction coupled with infrared thermography. This process is a possible alternative for magnetic particles testing and dye penetrant testing in the field of non-destructive testing. This work is divided into three main parties. At first, we have been interested in the characterization of optical and thermophysical properties of materials we used, in order to have good boundary conditions and also for the needs of temperatures fields measurements for validation. The second part concern the development of a numerical simulation model with two step approach: the first involves modelling temperature field with finite element method and the second details the infrared camera modelling. Innovative solutions were used to obtain model which integrates all parameters, with low time calculation. After validated temperature field, this model allows us to look for the process optimal parameters through numerical experimental designs
Ciccarone, Charles. "Utilisation d'ondes de surface à l'aide de scanners acoustiques sans contact pour le contrôle non destructif de structures en béton." Thesis, Centrale Lille Institut, 2020. http://www.theses.fr/2020CLIL0014.
This work proposes a method for the non-destructive testing of concrete for civil engineering structures.This method is based on the emission and reception - when the surface wave has passed through the material - ofacoustic sonic and ultrasonic waves. The waves used in this thesis are surface waves, as they have the property ofpenetrating the material to a depth equal to their wavelength. The auscultation of concrete is done using twoscanners: a first scanner applying this method with high frequency waves was used to characterize the concreteskin, while a second scanner using low frequency waves, developed within the framework of this work, made itpossible to characterize a concrete over the thickness of an entire wall. In order to determine the capabilities andlimitations of this method for the non-destructive testing of concrete, several pathologies or environmentalconditions of concrete were simulated in the laboratory on test specimens. These specimens were then examinednon-destructively with acoustic scanners and destructively with material tests. The pathologies or conditions inquestion were leaching, delamination, micro/macrocracking of the concrete, and its state of saturation. Comparisonof the results allowed us to conclude that this method and these scanners are able to detect and determine the depthof a leaching of concrete, as well as for a delamination within concrete, to follow the evolution of a saturation frontwithin a limestone but not yet within a concrete, and to detect and follow the stress and micro-cracking as well asthe evolution of macro-cracks, in particular thanks to automated measurements carried out in situ on the VeRCoRsstructure
Rouge, Clémence. "Modélisation du rayonnement ultrasonore par un traducteur EMAT dans une pièce ferromagnétique." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00942873.
Tout, Karim. "Automatic Vision System for Surface Inspection and Monitoring : Application to Wheel Inspection." Thesis, Troyes, 2018. http://www.theses.fr/2018TROY0008.
Visual inspection of finished products has always been one of the basic and most recognized applications of quality control in any industry. This inspection remains largely a manual process conducted by operators, and thus faces considerable limitations that make it unreliable. Therefore, it is necessary to automatize this inspection for better efficiency. The main goal of this thesis is to design an automatic visual inspection system for surface inspection and monitoring. The specific application of wheel inspection is considered to study the design and installation setup of the imaging system. Then, two inspection methods are developed: a defect detection method on the product’s surface and a change-point detection method in the parameters of the non-stationary inspection process. Because in an industrial context it is necessary to control the false alarm rate, the two proposed methods are cast into the framework of hypothesis testing theory. A parametric approach is proposed to model the non-anomalous part of the observations. The model parameters are estimated to design a statistical test whose performances are analytically known. Finally, the impact of illumination degradation on the defect detection performance is studied in order to predict the maintenance needs of the imaging system. Numerical results on a large set of real images highlight the relevance of the proposed approach
Roques, Aurélien. "Imagerie sismique appliquée à la caractérisation géométrique des fondations de pylônes électriques très haute tension." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENU020/document.
Near surface imaging is essential for geotechnics purpose. Characterization and identification of the first layers - between 0 and 10m - of the ground is necessary for many applications of national and regional development. Classical methods of imagery arouse a great interest as they are easy to use. In general, these numerical tools used in civil engineering have been first developped by seismic petroleum companies. The issue we are tackling comes to identifying the geometry of the foundations of very high voltage electric pylons using seismic imagery methods for french electricity transport and network. In particular, we assess the performances of the full waveform inversion and the reverse time migration. First, we explain the principle of these methods and then we implement them with a tool based on 2D modelisation which involves a reasonable computing time, contrary to 3D inversion carried out with today's means. Next, we show imagery results on synthetic and real data. Concerning, synthetic data, inversion makes it possible to identify the dimensions of the foundation as long as the velocity ratio between the foundation and the bedrock does not exceed 3. As to migration, it has good results with even much higher contrasts. Concerning real data, these two methods don't succeed in identifying the geometry of the foundation ; we inverted 3D synthetical data with our tool and show that the 3D property of data is prohibitive to 2D-inversion of real data with such an important 3D signature as the one we get on the foundation data
Gafsi, Rachid. "Capteurs de contraintes et de perturbations a fibres optiques." Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0509.
Fnaiech, Emna Amira. "Développement d’un outil de simulation du procédé de contrôle non destructif des tubes ferromagnétiques par un capteur à flux de fuite." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112311/document.
The principle of the non destructive testing by magnetic flux leakage (MFL) is to magnetize the part to be inspected by a magnetic field and to detect a flaw thanks to magnetic leakage field lines due to the strong decreasing of the magnetic permeability in the flawed region. In order to improve the performance of detection, the CEA and the Vallourec society collaborate to develop a numerical model dedicated to the virtual NDT of longitudinal defects in ferromagnetic tubes. The experimental system includes a magnetic circuit rotating at a constant speed around the tube to be inspected. The modeling task is started without considering the effects of the rotational speed, so the magnetostatic regime is considered to solve the modeling problem. In the framework of this thesis, we propose to compare a semi-analytical approach based on the formalism of integral equations method (IEM) and a purely numerical approach using finite element method (FEM).In the first part of this thesis, the theoretical formalism was established. A first simple discretization scheme is been implemented in the linear regime considering a constant magnetic permeability. This first numerical model has been validated for a simplified MFL configuration extracted and modified from the literature.For better detection, it is wishable to magnetically saturate the piece under-test. The ferromagnetic material is then characterized by a B(H) curve. Therefore, the second part of the thesis was devoted to the implementation of the model in the non-linear regime that takes into account this non-linear characteristic. Different discretization schemes have been studied in order to reduce the number of unknowns and the computational time. The originality of the thesis lies in the use of basis function of high order (Legendre polynomials) associated to a Galerkin approach for the discretization of integral equations. The first numerical result has been validated on a simplified MFL system. The first results of the experimental validation based on simulated data obtain by FEM have been performed in two steps. The first one consists to verify the distribution of the magnetic field for a ferromagnetic tube without any defect and in the magnetostatic regime. The objective of the second one was to compute the response of the flaw and to evaluate the effects of the rotational speed of the magnetic circuit around the tube
Caire, François. "Les équations de Maxwell covariantes pour le calcul rapide des champs diffractés par des conducteurs complexes. Application au Contrôle Non Destructif par courants de Foucault." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112284/document.
This PhD work concerns the development of fast numerical tools, dedicated to the computation of the electromagnetic interaction between a low frequency 3D current source and a complex conductor, presenting rough interfaces and/or conductivity (and/or permeability) variations. The main application is the simulation of the Eddy Current non-destructive testing process applied to complex specimens. Indeed, the existing semi-analytical models currently available in the CIVA simulation platform are limited to canonical geometries. The method we propose here is based on the covariant Maxwell equations, which allow us to consider the physical equations and relationships in a non-orthogonal coordinate system depending on the geometry of the specimen. Historically, this method (cf. C-method) has been developed in the framework of optical applications, particularly for the characterization of diffraction gratings. Here, we transpose this formalism into the quasi-static regime and we thus develop an innovative formulation of the Second Order Vector Potential formalism, widely used for the computation of the quasi-static fields in canonical geometries. Then, we determine numerically a set of modal solutions of the source-free Maxwell equations in the coordinate system introduced, and this allows us to represent the unknown fields as modal expansions in source-free domains. Then, the coefficients of these expansions are computed by introducing the source fields and enforcing the boundary conditions that the total fields must verify at the interfaces between media. In order to tackle the case of a layered conductor presenting rough interfaces, the generalized SOVP formalism is coupled with a recursive algorithm called the S-matrices. On the other hand, the application case of a complex shape specimen with depth-varying physical properties is treated by coupling the modal method we developed with a high-order numerical method: pseudo-spectral method. The validation of these codes is carried out numerically by comparison with a commercial finite element software in some particular configurations. Besides, the homogeneous case is also validated by comparison with experimental data
Ratsakou, Almpion. "Multi-physical modeling of thermographic inspection methods and fast imaging Fast models dedicated to simulation of eddy current thermography Fast simulation approach dedicated to infrared thermographic inspection of delaminated planar pieces Model based characterisation of delamination by means of thermographic inspection." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS002.
Thermographic inspection is a popular nondestructive testing (NdT) technique that provides images of temperature distribution over large areas at surfaces of tested workpieces. Detecting delaminations between metallic layers is the matter here. Simulation of these inspections indeed helps to complement experimental studies, evaluate performance in terms of detection and support model-based algorithms. A semi-analytical model based on a truncated region eigenfunction expansion for simulation of thermographic inspection is focused onto. The problem is solved in the Laplace domain w.r.t time, and the temperature distribution approximated by expanding it on a tensor product basis. Considered sources are lamps providing thermal excitation but may also be eddy current sources (leading to a coupled electromagnetic and heat problem). The description of the delaminations as thin air gaps between the workpiece layers proves to be equivalent with introduction of a surface resistance to the heat flow, enabling treatment via the applied modal approach without additional discretisation. Complementary computations by industry (Finite Element Method) and in-house (Finite Integration Technique) codes confirm the accuracy of the developments. Then, much attention is put on imaging and detection. A two-step procedure is devised, first denoising of raw signals and detection of any possible defect using a thermographic signal reconstruction leading to high spatial and temporal resolution in the transverse plane, completed by proper edge detection, second an iterative optimization being employed, with results of the first step used for regularization of a least-square scheme to characterize thicknesses and depths. All the above is illustrated by comprehensive numerical simulations in conditions close to practice
Zhang, Di. "Transducteurs ultrasonores capacitifs multiéléments à couplage air pour un contrôle non destructif à focalisation dynamique de matériaux : modélisation, simulations numériques et expériences." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14893/document.
This thesis focuses on the development of a Multi-Element Air-coupled Capacitive Ultrasonic Transducer (MEACUT) and its use in the field of non-destructive testing (NDT) of materials. A numerical model is used to simulate the translator, and to optimize its design. A prototype is then built and experimentally characterized to quantify its performance. Its originality lies in the fact that it has a broad frequency bandwidth while offering the possibility of a dynamic focusing. This prototype is then used for the detection of damage caused by impact, in a composite plate. It is clearly found that the spatial resolution of the inspection process employed (C-scan) is greatly improved thanks to the technical performance MEACUT. Finally, a 3D hybrid model is developed to simulate quickly and fully, the process of NDT. The good agreement obtained between numerical predictions and experimental measurements suggests that this simulation tool can be used to develop other NDT experiments, which may in turn exploit the performance of MEACUT
Lyonnet, Florian. "Modélisation du Contrôle Non Destructif ultrasonore de tubes métalliques pour l’activité nucléaire : approche 3D, confrontation à l’expérience et prise en compte de différentes géométries de défauts réels." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS566.
Reagrding the safety of civil nuclear installations, the metallic cladding that contains the fissile material has a great significance. Before filling, each tube is controlled by means of an automated ultrasonic inspection. For the French manufacturer Framatome, improving this process can have a positive impact on both quality and productivity. Since 2010, Framatome is conducting a project for the development of a numerical model of its ultrasonic inspection. In this work we propose a 3D model based on three independent steps which allows the re-utilization of optimized calculations. This model is able to simulate the echoes recorded during the inspection of a flawed product. We present a decoupling between the calculation of the flaw diffracted field and the incident field in the pipe. Our model uses both a semi-analytical method and a Finite Difference method to assess the reference computations of several flaws and several control configurations (inspection angle). A highly parallelized coupling code is proposed to reconstruct the echo signals from the reference fields. The improvement in term of computation time is evaluated and the results are compared with experimental results measured on an automated ultrasonic bench
Recoquillay, Arnaud. "Méthodes d'échantillonnage appliquées à l'imagerie de défauts dans un guide d'ondes élastiques." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLY001/document.
Widely used structures in an industrial context, such as plates, pipes or rails, can be considered as waveguides. Hence efficient Non Destructive Testing techniques are needed in order to detect defects in these structure during their maintenance. This work is about adapting a sampling method, the Linear Sampling Method, to the context of NDT for elastic waveguides. This context implies that the sollicitations and measurements must be on the surface of the waveguide in a time-dependent regime. A modal and multi-frequency formulation of the LSM, specific to waveguides, has been chosen to solve the problem. This formulation allows an efficient and physical regularization of the inverse problem, which is naturally ill-posed. An optimization of the number of sources and measurements and of their positioning is possible thanks to the methodology used to solve the problem. The scalar case of an acoustic waveguide is considered as a first step, while the vectorial case of an elastic waveguide, more complex by nature, is addressed in a second time.The efficiency of the method is at first tested on artificial data (numerically made), and then on real data obtained from experiments on metallic plates. These experiments show the feasibility of using sampling methods for Non Destructive Testing in an industrial context. In the case when only one sollicitation is available, the LSM can not be applied. A completely different approach is then used, which is called the ``exterior'' approach, coupling a mixed formulation of quasi-reversibility and a level-set method in order to recover the shape of the defect